Natural sand exhibits either plasticity or liquidity. For example, clay and plasticine can be shaped. They possess excellent plasticity but lack liquidity. Quicksand can flow but cannot be shaped. It possesses excellent liquidity but lacks plasticity. Although wet beach sand possesses plasticity and liquidity simultaneously, once the water is evaporated, it becomes dry and only has liquidity. It no longer possesses plasticity. Normally, natural sand does not possess plasticity and liquidity for a significant period of time.